Individuals were asked to mark either "male&quot or "female" to indicate their sex. For most cases in which sex was not reported, the appropriate entry was determined from the persons given (i.e., first) name and household relationship. Otherwise, sex was allocated according to the relationship to the householder and the age of the person. (For more information on allocation, see "2010 Census: Operational Overview and Accuracy of the Data.")

The sex ratio represents the balance between the male and female populations. Ratios above 100 indicate a larger male population, and ratios below 100 indicate a larger female population. This measure is derived by dividing the total number of males by the total number of females and then multiplying by 100. It is rounded to the nearest tenth.

The data on age were derived from answers to a two-part question (i.e., age and date of birth). The age classification for a person in census tabulations is the age of the person in completed years as of April 1, 2010, the census reference date. Both age and date of birth responses are used in combination to
determine the most accurate age for the person as of the census reference date. Inconsistently reported and missing values are assigned or allocated based on the values of other variables for that person, from other people in the household or from people in other households (i.e., hot-deck imputation).
Age data are tabulated in age groupings and single years of age. Data on age also are used to classify other characteristics in census tabulations.

This measure divides the age distribution into two equal parts: one-half of the cases falling below the median value and one-half above the value. Median age is computed on the basis of a single-year-of-age distribution using a linear interpolation method.

There is some tendency for respondents to provide their age as of the date they completed the census questionnaire or interview, not their age as of the census reference date. The two-part question and editing procedures have attempted to minimize the effect of this reporting problem on tabulations. Additionally, the current census age question displays the census reference date prominently, and interviewer training emphasizes the importance of collecting age as of the reference date.

Respondents sometimes round a persons age up if they were close to having a birthday. For most single years of age, the misstatements are largely offsetting. The problem is most pronounced at age 0. Also, there may have been more rounding up to age 1 to avoid reporting age as 0 years. (Age in completed months was not collected for infants under age 1.) Editing procedures correct this problem.

There is some respondent resistance to reporting the ages of babies in completed years (i.e., 0 years old when the baby is under 1 year old). Instead, babies ages are sometimes reported in months. The two-part question along with enhanced editing and data capture procedures correct much of this problem before the age data are finalized in tabulations. Additionally, the current census age question includes an instruction for babies ages to be answered as 0 years old when they are under 1 year old.

Age heaping is a common age misreporting error. Age heaping is the tendency for people to overreport ages (or years of birth) that end in certain digits (commonly digits 0 or 5) and underreport ages or years of birth ending in other digits. The two-part question helps minimize the effect of age heaping on the final tabulations.

Age data for centenarians have a history of data quality challenges. The counts in the 1970 and 1980 Censuses for people 100 years and over were substantially overstated. Editing and data collection methods have been enhanced in order to meet the data quality challenges for this population.

It also has been documented that the population aged 69 in the 1970 Census and the population aged 79 in the 1980 Census were overstated. The population aged 89 in 1990 and the population aged 99 in 2000 did not have an overstated count. (For more information on the design of the age question, see the Comparability section below.)

Age data have been collected in every census. However, there have been some differences in the way they have been collected and processed over time. In the 2010 Census (as in Census 2000), each individual provided both an age and an exact date of birth. The 1990 Census collected age and year of birth. Prior censuses had collected month and quarter of birth in addition to age and year of birth. The 1990 Census change was made so that coded information could be obtained for both age and year of birth.

In each census since 1940, the age of a person was assigned when it was not reported. In censuses before 1940, with the exception of 1880, people of unknown age were shown as a separate category. Since 1960, assignment of unknown age has been performed by a general procedure described as imputation. The specific procedures for imputing age have been different in each census. (For more information on imputation, see 2010 Census: Operational Overview and Accuracy of the Data.)

Excerpt from:

Social Explorer, U.S. Census Bureau; 2010 Census of Population and Housing, Summary File 1: Technical Documentation, Issued June 2011.

A person having origins in any of the original peoples of Hawaii, Guam, Samoa, or other Pacific Islands. It includes people who indicate their race as Native Hawaiian,Guamanian or Chamorro,Samoan, and Other Pacific Islander or provide other detailed Pacific Islander responses.Native Hawaiian-Includes people who indicate their race as Native Hawaiian or report entries such as Part Hawaiian or Hawaiian. Samoan-Includes people who indicate their race as Samoan or report entries such as American Samoan or Western Samoan. Tongan-Includes people who provide a response such as Tongan or Tonga.Other Polynesian-Includes people who provide a response of another Polynesian group, such as Tahitian, Tokelauan, or wrote in a generic term such as Polynesian.Guamanian or Chamorro-Includes people who indicate their race as Guamanian or Chamorro or report entries such as Chamorro or Guam.Marshallese-Includes people who provide a response such as Marshallese or Marshall Islands. Other Micronesian-Includes people who provide a response of another Micronesian group, such as Carolinian, Chuukese, I-Kiribati, Kosraean, Mariana Islander, Palauan, Pohnpeian, Saipanese, Yapese, or wrote in a generic term such as Micronesian.Fijian-Includes people who provide a response such as Fijian or Fiji.Other Melanesian-Includes people who provide a response of another Melanesian group, such as Guinean, Hebrides Islander, Solomon Islander, or wrote in a generic term such as Melanesian.Other Pacific Islander, not specified-Includes respondents who checked the Other Pacific Islander response category on the census questionnaire and did not write in a specific group or wrote in a generic term such as Pacific Islander.

Excerpt from:

Social Explorer, U.S. Census Bureau; 2010 Census of Population and Housing, Summary File 1: Technical Documentation, Issued June 2011.

The data on the Hispanic or Latino population were derived from answers to a question that was asked of all people. The terms Hispanic,Latino, and Spanish are used interchangeably. Some respondents identify with all three terms, while others may identify with only one of these three specific terms. People who identify with the terms Hispanic,Latino, or Spanish are those who classify themselves in one of the specific Hispanic, Latino, or Spanish categories listed on the questionnaire (Mexican,Puerto Rican, or Cuban) as well as those who indicate that they are another Hispanic, Latino, or Spanish origin. People who do not identify with one of the specific origins listed on the questionnaire but indicate that they are another Hispanic, Latino, or Spanish origin are those whose origins are from Spain, the Spanish-speaking countries of Central or South America, or the Dominican Republic. Up to two write-in responses to the another Hispanic, Latino, or Spanish origin category are coded.

Origin can be viewed as the heritage, nationality group, lineage, or country of birth of the person or the persons parents or ancestors before their arrival in the United States. People who identify their origin as Hispanic, Latino, or Spanish may be any race.

Some tabulations are shown by the origin of the householder. In all cases where the origin of households, families, or occupied housing units is classified as Hispanic, Latino, or Spanish, the origin of the householder is used. (See the discussion of householder under "Household Type and Relationship.")

If an individual did not provide a Hispanic origin response, his or her origin was allocated using specific rules of precedence of household relationship. For example, if origin was missing for a natural-born child in the household, then either the origin of the householder, another natural-born child, or spouse of the householder was allocated.
If Hispanic origin was not reported for anyone in the household and origin could not be obtained from a response to the race question, then their origin was assigned based on their prior census record (either from Census 2000 or the American Community Survey), if available. If not, then the Hispanic origin of a householder in a previously processed household with the same race was allocated. (For more information on allocation, see "2010 Census: Operational Overview and Accuracy of the Data.") As in Census 2000, surnames (Spanish and non-Spanish) were used to assist in allocating an origin or race.

There are four changes to the Hispanic origin question for the 2010 Census. First, the wording of the question differs from that in 2000. In 2000, the question asked if the person was Spanish/Hispanic/Latino. In 2010, the question asks if the person is of Hispanic, Latino, or Spanish origin. Second, in 2000, the question provided an instruction, Mark Ã½ the 'No'box if not Spanish/Hispanic/Latino. The 2010 Census question provided no specific instruction for non-Hispanics. Third, in 2010, the Yes, another Hispanic, Latino, or Spanish origin category provided examples of six Hispanic origin groups (Argentinean, Colombian, Dominican, Nicaraguan, Salvadoran, Spaniard, and so on) and instructed respondents to print origin. In 2000, no Hispanic origin examples were given. Finally, the fourth change was the addition of a new instruction in the 2010 Census that was not used in Census 2000. The instruction is stated as follows: NOTE: Please answer BOTH Question 8 about Hispanic origin and Question 9 about race. For this census, Hispanic origins are not races.

There were two changes to the Hispanic origin question for Census 2000. First, the sequence of the race and Hispanic origin questions for Census 2000 differs from that in 1990; in 1990, the race question preceded the Hispanic origin question. Testing prior to Census 2000 indicated that response to the Hispanic origin question could be improved by placing it before the race question without affecting the response to the race question. Second, there was an instruction preceding the Hispanic origin question indicating that respondents should answer both the Hispanic origin and the race questions. This instruction was added to give emphasis to the distinct concepts of the Hispanic origin and race questions, and emphasized the need for both pieces of information.

Furthermore, there was a change in the processing of the Hispanic origin and race responses. In the 1990 census, respondents provided Hispanic origin responses in the race question and race responses in the Hispanic origin question. In 1990, the Hispanic origin question and the race question had separate edits; therefore, although information may have been present on the questionnaire, it was not fully utilized due to the discrete nature of the edits. However, for Census 2000, there was a joint race and Hispanic origin edit that utilized Hispanic origin and race information regardless of the location.